Evaluation of Agronomic Characteristics, Disease Incidence, Yield Performance, and Aflatoxin Accumulation among Six Peanut Varieties (Arachis hypogea L.) Grown in Kenya

Diseases contribute to attainment of less than 50% of the local groundnut potential yield in Kenya. This study aimed to evaluate the agronomic characteristics (flowering and germination), disease incidence, yield performance (biomass, harvest index, 100-pod, 100-seed, and total pod weight), and aflatoxin accumulation in six peanut varieties. A field experiment was conducted using four newly improved peanut varieties: CG9, CG7, CG12, and ICGV-SM 90704 (Nsinjiro), and two locally used varieties: Homabay local (control) and 12991, and in a randomized complete block design with three replications. The disease identification followed the International Crop Research Institute for the Semi-Arid Tropics (ICRISAT) rating scale and further isolation of fungal contaminants was conducted by a direct plating technique using potato dextrose agar. The aflatoxin levels in the peanuts were determined after harvesting using the ultrahigh performance liquid chromatography and fluorescence detection (UHPLC-FLD) technique. ICGV-SM 90704 showed the least average disease incidence of 1.31 +/- 1.75%, (P < 0.05); the lowest total aflatoxin levels (1.82 +/- 1.41 mu g kg(-1)) with a range 0.00-0.85 mu g kg(-1) for total aflatoxins and a range 0.00-1.24 mu g kg(-1) for Aflatoxin B-1. The locally used varieties (12991 and the control) revealed the highest disease incidence (5.41 +/- 8.31% and 7.41 +/- 1.88%), respectively. ICGV-SM 90704 was the best performing among all the six varieties with an average total pod weight (9.22 +/- 1.19 kg), 100-pod weight (262.93 +/- 10.8 g), and biomass of (27.21 +/- 5.05 kg) per row. The 12991 variety and the control showed the least total pod weight (1.60 +/- 0.28 and 1.50 +/- 1.11 kg, respectively) (P = 0.0001). The newly improved varieties showed lower disease rates, low levels of aflatoxins, and higher yields than the locally used varieties.

Automated summary

Diseases are decreasing the potential yield of groundnut in Kenya by less than 50%. This study evaluated the agronomic characteristics, disease incidence, yield performance, and aflatoxin accumulation in six peanut varieties. The results showed that the newly improved varieties had lower disease rates, lower aflatoxin levels, and higher yields.